Base on the standard k-ωturbulent model,numerical method for solving three dimensional Reynolds Averaged Navier-Stokes(RANS)was adopted to study the aerothermal characteristics of the turbine blade with casing relati...Base on the standard k-ωturbulent model,numerical method for solving three dimensional Reynolds Averaged Navier-Stokes(RANS)was adopted to study the aerothermal characteristics of the turbine blade with casing relative motion.Experimental data were used to verify the effectiveness of the numerical method and turbulent model.The effect of blade tip clearance,geometry and relative motion on blade tip aerothermal characteristics were analyzed.The numerical results show that for the flat tip,relative motion can effectively suppress tip leakage and reduce leakage vortex size at rotating blade-static casing(BRCS)and static bladerotating casing(BSCR)conditions.A high level of heat transfer region can be observed near the leading edge at the conditions of rotating bladerotating casing(BRCS)and static bladestatic casing(BSCR).The blade tip heat transfer coefficient expands with the increase of tip clearance at different relative motion modes.At the brcs and bscs,the axial average heat transfer trend is the closest when the tip clearance is 1.5%H.The scraping vortex generated by relative motion at brcr and bscs inhib-its the development of leakage flow for squealer tip because of its sealing effect.High level of heat transfer region is also concentrated in the leading edge at brcr and bscs.The size of scraping vortex weakens with the increase of cavity depth.The distribution trend of the average heat transfer coefficient is similar in the two cases of relative static and relative motion,except for the case of 2.5%H cavity depth.展开更多
目的:分离纯化白花蛇舌草总多糖,研究其对环磷酰胺致免疫低下小鼠的免疫增强活性。方法:采用超滤技术分离纯化白花蛇舌草总多糖,高效凝胶渗透色谱-示差检测器方法测定相对分子质量,柱前衍生化HPLC分析其单糖组成;采用环磷酰胺致免疫低...目的:分离纯化白花蛇舌草总多糖,研究其对环磷酰胺致免疫低下小鼠的免疫增强活性。方法:采用超滤技术分离纯化白花蛇舌草总多糖,高效凝胶渗透色谱-示差检测器方法测定相对分子质量,柱前衍生化HPLC分析其单糖组成;采用环磷酰胺致免疫低下小鼠碳粒廓清试验研究其免疫活性。结果:从白花蛇舌草中分离得到1个单一多糖组分ODP-1,其相对分子质量20.88 k Da,单糖组成为甘露糖-鼠李糖-半乳糖醛酸-葡萄糖-半乳糖-阿拉伯糖,摩尔比0.005∶0.033∶0.575∶1.000∶0.144∶0.143;免疫活性试验结果表明,ODP-1可升高环磷酰胺致免疫低下小鼠廓清指数、吞噬指数、胸腺指数和脾指数。结论:白花蛇舌草多糖ODP-1为均一多糖,具有免疫增强活性。展开更多
Purpose: To evaluate posthepatectomy liver failure (PHLF) using gadoxetic acid-enhanced magnetic resonance imaging (MRI) with a measure of relative liver enhancement (RLE) on hepatobiliary phase images, thereby facili...Purpose: To evaluate posthepatectomy liver failure (PHLF) using gadoxetic acid-enhanced magnetic resonance imaging (MRI) with a measure of relative liver enhancement (RLE) on hepatobiliary phase images, thereby facilitating safe liver resection. Methods: Twenty patients in Child-Pugh class A underwent tumor excision surgery and indocyanine green (ICG) clearance of future remnant liver (FRL) (ICG-Krem) values were >0.05. PHLF was evaluated using the grading system of the International Study Group of Liver Surgery (ISGLS). The RLE value was defined as the signal gain percentage between the precontrast and hepatocellular images. In the whole liver and FRL, theRLE value measured the tumor-free liver parenchyma in RLE images. We examined the correlation between indocyanine green clearance (ICG-K) and MRI-based liver function in the whole liver. Preoperative PHLF evaluation was predicted using remnant hepatocellular uptake index (rHUI), remnant RLE (rRLE), coefficient variation of Rrle [Cv(rRLE)], and ICG-Krem corrected by heterogeneous liver function(HLF-ICG-Krem). Results: HLF-ICG-Krem and rRLE values correlated with INRs after postoperative day five (r = -0.55 and 0.46, p = 0.01 and 0.04, respectively). Furthermore, HLF-ICG-Krem values ≤0.05 detected two patients with higher INRs after postoperative day five. On the other hand, neither rHUI nor Cv(rRLE) was correlated with INRs after postoperative day five (r = 0.28, and -0.03, respectively;p >0.05 for both). HLF-ICG-Krem was significantly lower with PHLF than without PHLF (p = 0.005). Conclusion: HLF-ICG-Krem is useful for evaluating PHLF more correctly.展开更多
基金National Natural Science Foundation of China(No.52006178)National Key R&D Program of China(No.Y2019-Ⅷ-0007-0168)the Fundamental Research Funds for the Central Universities and the Innovation Capacity Support Plan in Shaanxi Province of China(Grant No.2023-CX-TD-19)。
文摘Base on the standard k-ωturbulent model,numerical method for solving three dimensional Reynolds Averaged Navier-Stokes(RANS)was adopted to study the aerothermal characteristics of the turbine blade with casing relative motion.Experimental data were used to verify the effectiveness of the numerical method and turbulent model.The effect of blade tip clearance,geometry and relative motion on blade tip aerothermal characteristics were analyzed.The numerical results show that for the flat tip,relative motion can effectively suppress tip leakage and reduce leakage vortex size at rotating blade-static casing(BRCS)and static bladerotating casing(BSCR)conditions.A high level of heat transfer region can be observed near the leading edge at the conditions of rotating bladerotating casing(BRCS)and static bladestatic casing(BSCR).The blade tip heat transfer coefficient expands with the increase of tip clearance at different relative motion modes.At the brcs and bscs,the axial average heat transfer trend is the closest when the tip clearance is 1.5%H.The scraping vortex generated by relative motion at brcr and bscs inhib-its the development of leakage flow for squealer tip because of its sealing effect.High level of heat transfer region is also concentrated in the leading edge at brcr and bscs.The size of scraping vortex weakens with the increase of cavity depth.The distribution trend of the average heat transfer coefficient is similar in the two cases of relative static and relative motion,except for the case of 2.5%H cavity depth.
文摘目的:分离纯化白花蛇舌草总多糖,研究其对环磷酰胺致免疫低下小鼠的免疫增强活性。方法:采用超滤技术分离纯化白花蛇舌草总多糖,高效凝胶渗透色谱-示差检测器方法测定相对分子质量,柱前衍生化HPLC分析其单糖组成;采用环磷酰胺致免疫低下小鼠碳粒廓清试验研究其免疫活性。结果:从白花蛇舌草中分离得到1个单一多糖组分ODP-1,其相对分子质量20.88 k Da,单糖组成为甘露糖-鼠李糖-半乳糖醛酸-葡萄糖-半乳糖-阿拉伯糖,摩尔比0.005∶0.033∶0.575∶1.000∶0.144∶0.143;免疫活性试验结果表明,ODP-1可升高环磷酰胺致免疫低下小鼠廓清指数、吞噬指数、胸腺指数和脾指数。结论:白花蛇舌草多糖ODP-1为均一多糖,具有免疫增强活性。
文摘Purpose: To evaluate posthepatectomy liver failure (PHLF) using gadoxetic acid-enhanced magnetic resonance imaging (MRI) with a measure of relative liver enhancement (RLE) on hepatobiliary phase images, thereby facilitating safe liver resection. Methods: Twenty patients in Child-Pugh class A underwent tumor excision surgery and indocyanine green (ICG) clearance of future remnant liver (FRL) (ICG-Krem) values were >0.05. PHLF was evaluated using the grading system of the International Study Group of Liver Surgery (ISGLS). The RLE value was defined as the signal gain percentage between the precontrast and hepatocellular images. In the whole liver and FRL, theRLE value measured the tumor-free liver parenchyma in RLE images. We examined the correlation between indocyanine green clearance (ICG-K) and MRI-based liver function in the whole liver. Preoperative PHLF evaluation was predicted using remnant hepatocellular uptake index (rHUI), remnant RLE (rRLE), coefficient variation of Rrle [Cv(rRLE)], and ICG-Krem corrected by heterogeneous liver function(HLF-ICG-Krem). Results: HLF-ICG-Krem and rRLE values correlated with INRs after postoperative day five (r = -0.55 and 0.46, p = 0.01 and 0.04, respectively). Furthermore, HLF-ICG-Krem values ≤0.05 detected two patients with higher INRs after postoperative day five. On the other hand, neither rHUI nor Cv(rRLE) was correlated with INRs after postoperative day five (r = 0.28, and -0.03, respectively;p >0.05 for both). HLF-ICG-Krem was significantly lower with PHLF than without PHLF (p = 0.005). Conclusion: HLF-ICG-Krem is useful for evaluating PHLF more correctly.
